A Retrospective (Post-Marketing) Case Series of Patients Receiving Intramuscular (IM) Olanzapine outside of Product Doses and Indications (Off-Label): Assessing Safety and Tolerability

Abstract

Introduction: Intramuscular (IM) olanzapine has been approved for the management of acute agitation/psychosis secondary to schizophrenia, bipolar disorder, and dementia, in a dose not to exceed 10 mg per injection and 30 mg per day. Many other clinical situations exist in which patients are acutely agitated and in whom IM olanzapine might be warranted at recommended or higher doses. We systematically reviewed data on 8 such patients, during 10 inpatient admissions, to assess the overall safety and tolerability of this approach. Methods: Using a standardized data recording sheet, we retrospectively collected information on 10 inpatient admissions between 2004 and 2007, in which IM olanzapine was administered outside of product dosing and/or indication guidelines. We present composite data and the details of each case individually. Results: Records of eight patients (5 males, 3 females; mean age/age range = 43.9/18-77 years) were reviewed over 10 inpatient admissions, 5 to Psychiatry, 4 to Surgery, and one to Internal Medicine. Indications for admission were mania (2), schizophrenia (1), schizoaffective disorder (2), brain injury (2), sepsis (1), sepsis with respiratory failure (1), and cancer (1). Five patients were intoxicated with or experienced withdrawal from alcohol and/or drugs, likely adding to their agitation. Only one symptomatic episode of orthostatic hypotension occurred, in a patient with comorbid C. difficile colitis, which resolved when antibiotics were initiated and olanzapine discontinued; olanzapine IM was successfully reinstituted 2 days later, without incident. No other significant adverse events or side effects were ascribed to IM olanzapine. Conclusions: Intramuscular olanzapine may be safe to use outside of product dosing and indication guidelines. Randomized clinical trials are warranted to study such off-label use further.